#include <string.h>

int strcmp(const char *s1, const char *s2) {
	while ((*s1) && (*s1 == *s2)) {
		++s1;
		++s2;
	}
	return *s1 - *s2;
}

#ifdef _TEST_
#include <stdio.h>

int main() {
	char szKey[] = "apple";
	char szInput[80];
	do {
		printf ("Guess my favourite fruit? ");
		gets (szInput);
	} while (strcmp (szKey, szInput) != 0);
	puts ("Correct answer!");
	return 0;
}

#endif
